https://www.sqlite.org/c3ref/column_blob.html
The sqlite3_column_type() routine returns the datatype code for the initial data type of the result column. The returned value is one of SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, or SQLITE_NULL. The return value of sqlite3_column_type() can be used to decide which of the first six interface should be used to extract the column value. The value returned by sqlite3_column_type() is only meaningful if no automatic type conversions have occurred for the value in question. After a type conversion, the result of calling sqlite3_column_type() is undefined, though harmless. Future versions of SQLite may change the behavior of sqlite3_column_type() following a type conversion. ----- First search... https://stackoverflow.com/questions/11753871/getting-the-type-of-a-column-in-sqlite PRAGMA table_info(table1); will dump the table information, e.g. cid|name |type |notnull |dflt_value |pk0 |id_fields_starring |INTEGER |0 | |11 |fields_descriptor_id |INTEGER |1 | |02 |starring_id |INTEGER |1 | |03 |form_mandatory |INTEGER |1 |1 |04 |form_visible |INTEGER |1 |1 |0 http://www.sqlite.org/datatype3.html NULL. The value is a NULL value. INTEGER. The value is a signed integer, stored in 1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value. REAL. The value is a floating point value, stored as an 8-byte IEEE floating point number. TEXT. The value is a text string, stored using the database encoding (UTF-8, UTF-16BE or UTF-16LE). BLOB. The value is a blob of data, stored exactly as it was input. On Sat, May 5, 2018 at 2:59 AM, Max Vlasov <max.vla...@gmail.com> wrote: > Hi, > > What is the best way to map a field type as it is provided in create table > statement to sqlite3_result_* function call? > > More specifically, I have a virtual table implementation where a raw table > data provided and the corresponding field definition part ([FieldA] TEXT, > [FieldB] FLOAT....). When asked by sqlite to fetch the column data I'd like > to convert the text representation of a column to the best "type" and make > the best sqlite3_result_* call. So I need probably the same machinery as > sqlite itself when it handles type affinity. > > I found a function in the sources, sqlite3AffinityType, that probably > serves the goal, but it's private. Also, a suggestion to implement a > similar functionality was made by Jay A. Kreibich is in the mail list > (mentioning sqlite3AffinityType) > > On Thu, Jul 8, 2010 at 12:23 PM, Jay A. Kreibich <j...@kreibi.ch> wrote: > >> Other suggestions? > > > > This has nothing to do with WAL, but it might be nice to expose > > the logic that does SQL-type => SQLite-affinity mappings > > (i.e. sqlite3AffinityType()): > > > > int sqlite3_get_affinity( const char *type ); > > > > Takes a string that contains an SQL type. Returns one of: > > > > SQLITE_AFF_TEXT, SQLITE_AFF_NONE, SQLITE_AFF_NUMERIC, > > SQLITE_AFF_INTEGER, SQLITE_AFF_REAL. > > But I suppose sqlite3_get_affinity or similar function was never > implemented. > I know that I probably might mimic the sqlite machinery knowing it's not > that complex, but it is always better to rely on the approved logic of > sqlite itself. > > Thanks, > > Max > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
